From mboxrd@z Thu Jan 1 00:00:00 1970 From: bugtrack@alsa-project.org Subject: [ALSA - driver 0001151]: Audigy sampling rate seems off Date: Fri, 3 Jun 2005 10:59:19 +0200 Message-ID: <965e9c83c8aa650cc2c20deb97b92877@bugtrack.alsa-project.org> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Return-path: Received: from bugtrack.alsa-project.org (gate.perex.cz [82.113.61.162]) by alsa.jcu.cz (ALSA's E-mail Delivery System) with ESMTP id BF02E1A7 for ; Fri, 3 Jun 2005 10:59:19 +0200 (MEST) Sender: alsa-devel-admin@lists.sourceforge.net Errors-To: alsa-devel-admin@lists.sourceforge.net List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , List-Archive: To: alsa-devel@alsa-project.org List-Id: alsa-devel@alsa-project.org A NOTE has been added to this issue. ====================================================================== ====================================================================== Reported By: felix Assigned To: ====================================================================== Project: ALSA - driver Issue ID: 1151 Category: PCI - emu10k1 Reproducibility: always Severity: minor Priority: normal Status: new Distribution: Suse 9.1 Kernel Version: 2.6.5-7.147-default ====================================================================== Date Submitted: 06-02-2005 23:07 CEST Last Modified: 06-03-2005 10:59 CEST ====================================================================== Summary: Audigy sampling rate seems off Description: I'm doing an experiment that involves generating a tone, sending it out the sound card and into a (passive) circuit, and recording from the circuit back into line in at the same time. When I play a sample: mono, 8kHz sample rate, containing a synthetic 1kHz sin signal, the recording I get is of a signal 1000.12Hz. If I send 100Hz, I get back 100.012Hz. I use 'snd' to do a 256K-point FFT across a 10 second sample just to be sure. I've also verified this using FFTW and correlation-based programs of my own. I've also verified that the reference 1kHz and 100Hz signals are exact. As a sanity check, I tried the same experiment on the built-in sound card on that same PC. The signals come back correct. Note the seeming coincidence that the frequency of the signal coming back is 1/8000 higher than the signal output. I've never seen anything like it. Not that I've been looking before... ====================================================================== ---------------------------------------------------------------------- sst4 - 06-03-05 00:29 ---------------------------------------------------------------------- If it's rather off by 1/8192 (8192 is 2 to 13th power), then it'd look very much programmatic. Just an observation - I know nothing about "audigy". ---------------------------------------------------------------------- perex - 06-03-05 10:59 ---------------------------------------------------------------------- Note that the routine which calculates "pitch" for playback is in alsa-kernel/pci/emu10k1/emupcm.c - emu10k1_calc_pitch_target(). It's quite simple, so you may do experiments with it. Also, upgrade to latest ALSA 1.0.9, there are some cleanups for the sample cache, and it might be also related. Issue History Date Modified Username Field Change ====================================================================== 06-02-05 23:07 felix New Issue 06-02-05 23:07 felix Distribution => Suse 9.1 06-02-05 23:07 felix Kernel Version => 2.6.5-7.147-default 06-03-05 00:29 sst4 Note Added: 0004879 06-03-05 10:59 perex Note Added: 0004883 ====================================================================== ------------------------------------------------------- This SF.Net email is sponsored by Yahoo. Introducing Yahoo! Search Developer Network - Create apps using Yahoo! Search APIs Find out how you can build Yahoo! directly into your own Applications - visit http://developer.yahoo.net/?fr=offad-ysdn-ostg-q22005